Bessemer process | metallurgy | Britannica.com Bessemer process Sir Henry Bessemer Bessemer process, the first method discovered for mass-producing steel . Though named after Sir Henry Bessemer of England, the process evolved from the contributions of many investigators before it could be used on a broad commercial basis. It was apparently conceived independently and almost concurrently by Bessemer and by William Kelly of the United States . As early as 1847, Kelly, a businessman-scientist of Pittsburgh , Pa., began experiments aimed at developing a revolutionary means of removing impurities from pig iron by an air blast; Kelly theorized that not only would the air, injected into the molten iron , supply oxygen to react with the impurities, converting them into oxides separable as slag , but that the heat evolved in these reactions would increase the temperature of the mass, keeping it from solidifying during the operation. After several failures, he succeeded in proving his theory and rapidly producing steel ingots. Bessemer furnace, Kelham Island Museum, Sheffield, England. Wikityke In 1856 Bessemer, working independently in Sheffield , developed and patented the same process.

Whereas Kelly had been unable to perfect the process owing to a lack of financial resources, Bessemer was able to develop it into a commercial success. Another Englishman, Robert Forester Mushet , found that adding an alloy of carbon , manganese , and iron after the air-blowing was complete restored the carbon content of the steel while neutralizing the effect of remaining impurities, notably sulfur. A Swedish ironmaster, Goran Goransson, redesigned the Bessemer furnace, or converter, making it reliable in performance. The end result was a means of mass-producing steel. The resultant volume of low-cost steel in Britain and the United States soon revolutionized building construction and provided steel to replace iron in railroad rails and many other uses. The Bessemer converter is a cylindrical steel pot approximately 6 m (20 feet) high, originally lined with a siliceous refractory . Air is blown in through openings (tuyeres) near the bottom, creating oxides of silicon and manganese, which become part of the slag, and of carbon, which are carried out in the stream of air. Within a few minutes an ingot of steel can be produced, ready for the forge or rolling mill.

Similar Topics Bessemer Converter | Sheffield Industrial Museums Trust Bessemer Converter Kelham Island Museum The Bessemer Converter is one of only three converters left in the world. It was used by the British Steel Corporation in Workington until 1975(4?) and produced the last Bessemer Steel made in Britain in 1974. It was brought to the Museum in 1978 as an example of the revolutionary steelmaking process which first took off in Sheffield. The Bessemer process - the conversion of iron into steel - was invented and patented by Henry Bessemer in 1856. The egg-shaped converter was tilted down to pour molten pig iron in through the top, then swung back to a vertical position and a blast of air was blown through the base of the converter in a dramatic fiery ‘blow'. Spectacular but dangerous flames and fountains shot out of the top of the converter. The converter was tilted again and the newly made steel was teemed or poured out. The first converters could make seven tonnes of steel in half an hour.

In 1858 Henry Bessemer moved to Sheffield and licensed his method to two steelmakers, John Brown and George Cammell, who both began to produce Bessemer Steel on an unprecedented scale by 1860. Others soon followed and within 20 years, Sheffield alone was producing 10,000 tons of Bessemer steel every week (this was almost a quarter of the country's total output). The invention marked the beginning of mass steel production, as huge amounts could be produced in a relatively short time compared to crucible steel production. The steel was most widely used for the railways that were stretching around the world. Plan Your Visit Making the Modern World - New science, new materials, new power New science, new materials, new power New steel: The Bessemer converter The earliest evidence of steel production is from sub-Saharan Africa in the first millennium BC. The Haya people, from an area now in north western Tanzania, developed a technology for producing high-grade carbon steel that was in use until the 1950s. The Hayas used a cone-shaped clay kiln to heat the iron ore, which was pre-roasted to increase its carbon content.

Air was pumped into the base of the kiln, passing through the furnace through clay pipes, before arriving inside the kiln. This preheated air allowed very high temperatures to be achieved inside the kiln, improving fuel efficiency as well as the quality of the iron. In Europe before Henry Bessemer invented his Converter in 1856, steel had been an expensive, high-quality metal made by artisans. It was used mainly for tools and weapons while engineers generally preferred wrought and cast iron. The Bessemer Converter had a huge impact on the use of steel. Its cheap, easily produced, medium-quality steel quickly replaced iron for all large-scale engineering work and transformed both industry and society in © Science Museum/Science & Society Picture Library Europe and the United States. When cheap steel products were imported into Africa in the early twentieth century, it also spelled the end of the Hayas' steel industry. © Science Museum/Science & Society Picture Library The Bessemer method converts molten pig iron into steel in a squat, egg-shaped bowl. Blasts of cold air are blown through the liquid metal via perforations in the bowl's base. The air burns off excess carbon and other impurities.

When the iron is nearly purified, more carbon might be added. Finally the bowl is tilted down and the newly made steel poured into a ladle ready to cast into ingot moulds. The Bessemer process was simple but the visual effect was extraordinary. In 1893, an over-excited journalist at McClure's Magazine wrote: A fountain of sparks arose, gorgeous as ten thousand rockets, and fell with a beautiful curve, like the petals of some enormous flower…. Down came the vessel, until out of it streamed the smooth flow of terribly beautiful molten metal. In America the introduction of the Bessemer Converter had an enormous impact on an expanding society. The availability of cheap, durable steel rails allowed pioneers to build over 30,000 miles of railroad and colonise the western part of the country. © Science Museum/Science & Society Picture Library The early period of this expansion was satisfied by Britain's steel railmakers, particularly those in Sheffield, which remained the centre of the trade until 1870. The steel industry, along with coal, textiles and iron, had enabled Britain to build its Empire.

But by the end of the nineteenth century the industry was strongest in the United States, whose steel producers increased efficiency and dropped prices. As well as railways, the Bessemer Converter was instrumental in the production of armaments. Guns, cannons and warships became relatively inexpensive to produce, boosting America's military power. After 1900 the Bessemer process was rapidly replaced by an alternative method, the Siemens-Martin or open hearth process. This allowed precise control of temperatures resulting in better quality steel. © Science Museum/Science & Society Picture Library Steel frames were used to build towering skyscrapers as the rural population moved to the booming American cities. New sheet steel led to the development of myriad consumer products including washing machines, electric ovens, refrigerators and, perhaps most importantly of all, the automobile. By 1914 automobile manufacturers had become the leading consumers of steel. The last Bessemer Converter in North America went out of commission in the 1960s. Resource Descriptions The squat, egg-shaped Bessemer Converter seemed an unlikely candidate to lead a revolution in manufacturing. Sir Henry Bessemer. Ingot of Bessemer steel.

Steel is an alloy of iron, carbon and small amounts of other elements. Iron contains impurities in the form of silicon, phosphorus, sulphur and manganese; the production of steel involves the removal of these impurities (known as slag) and the addition of desirable alloying elements. Manufacturing Bessemer steel. Bessemer process Encyclopedia > Earth and the Environment > Minerals, Mining, and Metallurgy > Metallurgy and Mining: Terms and Concepts Bessemer process Bessemer process (bĕsˈəmər) [ key ] [for Sir Henry Bessemer ], industrial process for the manufacture of steel from molten pig iron. The principle involved is that of oxidation of the impurities in the iron by the oxygen of air that is blown through the molten iron; the heat of oxidation raises the temperature of the mass and keeps it molten during operation. The process is carried on in a large container called the Bessemer converter, which is made of steel and has a lining of silica and clay or of dolomite. The capacity is from 8 to 30 tons of molten iron; the usual charge is 15 or 18 tons. The converter is egg-shaped.

At its narrow upper end it has an opening through which the iron to be treated is introduced and the finished product is poured out. The wide end, or bottom, has a number of perforations (tuyères) through which the air is forced upward into the converter during operation. The container is set on pivots (trunnions) so that it can be tilted at an angle to receive the charge, turned upright during the "blow," and inclined for pouring the molten steel after the operation is complete. As the air passes upward through the molten pig iron, impurities such as silicon, manganese, and carbon unite with the oxygen in the air to form oxides; the carbon monoxide burns off with a blue flame and the other impurities form slag. Dolomite is used as the converter lining when the phosphorus content is high; the process is then called basic Bessemer. The silica and clay lining is used in the acid Bessemer, in which phosphorus is not removed. In order to provide the elements necessary to give the steel the desired properties, another substance (often spiegeleisen, an iron-carbon-manganese alloy) is usually added to the molten metal after the oxidation is completed.

The converter is then emptied into ladles from which the steel is poured into molds; the slag is left behind. The whole process is completed in 15 to 20 min. The Bessemer process was superseded by the open-hearth process (see steel ). See also metallurgy . The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved. Bessemer converter | Define Bessemer converter at Dictionary.com Bessemer converter the refractory-lined metal container in which steel is produced by the Bessemer process. Origin of Bessemer converter British Dictionary definitions for Bessemer converter Expand a refractory-lined furnace used to convert pig iron into steel by the Bessemer process Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd.

1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012 People invent new words all the time, but which ones actually make it? Word of the Day Bessemer process - definition of Bessemer process by The Free Dictionary Bessemer process - definition of Bessemer process by The Free Dictionary Also found in: Thesaurus , Encyclopedia , Wikipedia . Bessemer process n. A method for making steel by blasting compressed air through molten iron to burn out excess carbon and impurities. [After Sir Henry Bessemer.] Bessemer process n 1. (Metallurgy) (formerly) a process for producing steel by blowing air through molten pig iron at about 1250°C in a Bessemer converter: silicon, manganese, and phosphorus impurities are removed and the carbon content is controlled 2.

(Metallurgy) a similar process for removing sulphur and iron from copper matte [C19: named after Sir Henry Bessemer (1813–98), English engineer] Bes′semer proc`ess n. a process of producing steel in which impurities are removed by forcing air through molten iron in a refractory-lined metal container (Bes′semer convert`er). Bes·se·mer process (bĕs′ə-mər) A method for making steel by forcing compressed air through molten iron to burn out carbon and other impurities. ThesaurusAntonymsRelated WordsSynonymsLegend: Steel Manufacturing Process Explored: Bessemer, Open-hearth, Crucible, Cementation, and Electric Process Electric Process Let’s look at these one by one. Cementation Process: In this process wrought iron bars are introduced in a furnace in between powdered charcoal layers and are subjected to a very high temperature – about 7000 Celsius for about a week to fortnight depending upon the required quality of the steel. The conditions slowly diffuse carbon into iron and cause the carbon to become dissolved in the iron, raising the carbon percentage.

Steel obtained from this process is called “blister steel" due to the blister-like marks formed on the surface due to the evolved gases during the manufacturing process. The carbon amount here is usually around 0.75% to 1.5%. Crucible Process: The process involves heating of either blister steel fragments or short lengths of wrought iron bars mixed with charcoal inside fire clay crucibles. The resulting molten steel is allowed to run through iron moulds. Such steel is called “cast iron." Cast steel is extremely hard and perfectly homogenous. These are specifically used for making cutting tools and the finest cutlery items. Bessemer Process: In this process pig iron is melted in a cupola and poured into Bessemer converter which is pear shaped and has a steel shell lined with refractory material. It’s pivoted on trunnions so as to facilitate tilting, pouring or charging. Once the above converter is charged with molten pig iron, a strong thrust of air is blasted across the molten mass for about 20 minutes through nozzles provided at the bottom of the vessel. The process oxidizes all traces of the carbon and silicon present, leaving the converter with pure iron.

After this the blasting of air is stopped and the specified amount of ferro-manganese is added to it for the sake of including the recommended content of carbon and manganese to the steel. The air blasted procedure is again initiated for some time, ensuring perfect mixing of the alloy. The converter is then tilted so that the molten material can be discharged into the ladles. In the final step the molten alloy is shifted into rectangular moulds where it’s obtained in the form of solid ingots. Open Hearth Process: The specialty of open-hearth furnaces is the extreme heat that can be obtained from them due to their regenerative process. The charge of pig iron, steel scrap, iron ore, and flux are together kept in a shallow container with a flame burning above it. The process is initiated inside reverbaratory gas-fired regenerative furnaces for greater efficiency. Regenerators are placed below the furnace and positioned in two pairs. The pairs are heated alternately through the passage of hot gases given out from the furnace in their route to the chimney. This heat is retained by the regenerators and is reversed and given back to the furnace. This heat exchange procedure helps the furnace to maintain high temperatures even with less fuels.

Once the furnace is charged with pig iron, pure oxidizing ores like haematite are added to it from time to time, which helps oxidization and the removal of impurities like silicon, carbon, and manganese in the pig iron. Spiegel is also introduced when the carbon content becomes less than 0.1%, and ferro-manganese after the metal is tapped out into the ladle. Ferro-manganese becomes important for restoring malleability and also for carburizing the iron . Electric Process: In this process electric arc or electric high frequency furnaces are used. In electric arc furnaces which are more common among the two processes, high voltage electric arc struck between carbon electrodes and the charge becomes the source of a very high temperature. The charge is collected directly from an open hearth furnace, the intense arc heat keeps the charge in its molten state, and the impurities are removed in the form of slag. The high frequency furnace is based on the principle that when high frequency alternating current is applied to steel, eddy currents starts flowing in them. If this induction is made very strong, it can heat up the steel and melt it.

Electric furnaces are more advantageous compared to the other steel manufacturing processes due to the absence of evolving gases, fumes, etc., which normally become a major problem with fuel operated furnaces. Image Credit: From the book "An introduction to the study of metallurgy", By Sir William Chandler Roberts-Austen slide 2 of 2 1.2_invent.html INVENTING THE PROCESS An invention must be nursed as a mother nurses her baby, or it inevitably perishes. 10 From the start, the Bessemer process -- the most important technique for making steel in the nineteenth century -- was bound up with powerful institutions; in this respect, its transfer and development by American railroads continued a pattern set out by its English inventor. While at least five English or American inventors devised processes for making steel by blowing steam or air through molten iron, it was Henry Bessemer's process that became the most widely used. His technical ingenuity was only the start.

A close examination of Bessemer's inventive activities shows that his process was inspired by association with powerful institutions, especially the military, that his efforts to develop and commercialize his process rescued it from failure and obscurity, and that his considerable flair for publicity and patronage were as important to his overall success as his original technical conception. "The Messrs. Bessemer, the great steel makers, [have] long been known to keep their own leading article writer.... Mr. Bessemer's investing in what some might deem a luxury was a powerful natural step on his part," wrote the Engineer. "Few of the many investments Mr. Bessemer has made during his career have been more promising." "Bessemerizing" was understood by his peers as a social as well as technical achievement. 11 As a young man, Henry Bessemer proved himself adept at lining up prominent patrons behind his mechanical inventions. The son of a French emigre who had talked his way into the English Mint, then retired to the countryside, Bessemer came to London at age 17 and made a living by executing artistic castings, printing specialty items, and making metal dies.

By the time he was 23 his experiments in electrometallurgy had attracted the attention of Andrew Ure, the prominent philosopher of industrialism. Around the same time, Bessemer made his first notable invention, for the Inland Revenue Office. He devised a dated stamp that prevented the fraudulent reuse of revenue stamps on official documents. The invention reportedly brought the Treasury an additional £100,000 per year, and Bessemer a knighthood in 1879. 12 In the meantime Bessemer's inventive career flourished with his flair for high profile publicity. Windsor Castle tendered the first order for his novel machine-made embossed velvet, and the pioneering Coalbrookdale Iron Company tendered the first order for his machine-made bronze powder. In fact, a handsome income from manufacturing powdered bronze, which he conducted with great secrecy for some forty years, was the support for his inventive activities. At Baxter House, in the St. Pancras district of London, Bessemer set up an experimental factory and laboratory.

His work there, when added to his earlier efforts, netted Bessemer 34 patents on new methods for casting and setting type, for manufacturing paints, oils, varnishes, sugar, and plate glass, for constructing railway carriages, centrifugal pumps, and projectiles, and for ventilating coal mines. 13 While Bessemer had achieved modest success as a mechanical inventor, it was a military problem that led him to the manufacture of iron. "At the time when the Crimean War broke out," he wrote, "the attention of many persons was directed to the state of our armaments." Bessemer identified rifled ordnance as a key problem, and he devised a way of imparting spin to projectiles shot from a smooth-bore gun. When the British War Office rejected his idea Bessemer took it to France. In 1854, after demonstrating the revolving projectile at Vincennes, Bessemer heard from the officer in charge, Commander Claude Etienne Minié, the rifle inventor, that he mistrusted firing the heavy thirty-pound shot from the available twelve-pounder cast iron guns. Minié asked whether a new type of gun could be made to withstand such heavy projectiles.

This observation, by Bessemer's account, "instantly forced on my attention the real difficulty," i.e., withstanding the "heavy strains" caused by the projectiles, and he returned immediately to Baxter House determined "to study the whole question of metals suitable for the construction of guns." Within three weeks he filed the first in a famous series of patents on iron and steel. 14 Assisted at Baxter House by his brother-in-law, Bessemer began his gun-metal experiments by melting various mixtures of pig iron (the crude product of smelting iron ore), blister steel (a refined and expensive metal), and scrap in a standard iron-melting reverberatory furnace, producing enough metal to cast a model gun. 15 Then Bessemer's experiments took an unexpected twist: Some pieces of pig iron on one side of the bath attracted my attention by remaining unmelted in the great heat of the furnace, and I turned on a little more air through the fire-bridge with the intention of increasing the combustion. On again opening the furnace door, after an interval of half an hour, these two pieces of pig still remained unfused.

I then took an iron bar, with the intention of pushing them into the bath, when I discovered that they were merely thin shells of decarburised iron ... showing that atmospheric air alone was capable of wholly decarburising grey pig iron, and converting it into malleable iron without puddling or any other manipulation. Thus a new direction was given to my thoughts, and after due deliberation I became convinced that if air could be brought into contact with a sufficiently extensive surface of molten crude iron, it would rapidly convert it into malleable iron. 16 This anomaly, the shell of decarburized iron, led Bessemer to invent a process that reshaped the iron and steel industry. INSERT Figure I.1 Bessemer's Early Steel Making Experiments (1854-55) Now, hot on the trail, Bessemer built a crucible with a blow pipe extended into its center. Into the crucible he poured about 10 pounds of unrefined pig iron and then placed the apparatus into a hot furnace; after 30 minutes of blowing air into the metal, he found the crude iron had become malleable iron.

This experiment proved air could decarburize pig iron, turning it into a useful product, yet the furnace surrounding the crucible still consumed copious amounts of fuel. Bessemer's real insight was to get rid of the furnace entirely. For this he built a four-foot tall, open-mouthed cylinder with openings, or tuyères, to blow air into the metal from the bottom. As Bessemer related it, at first the blast bubbled quietly through the seven hundredweight of molten pig iron in the vessel, with the opening emitting some sparks and hot gases. Suddenly, after ten minutes, white flames shot forth. "Then followed a succession of mild explosions, throwing molten slags and splashes of metal high up into the air, the apparatus becoming a veritable volcano in a state of active eruption." Unable to approach the out-of-control converter, Bessemer and his assistants could only watch until the eruption quieted after ten minutes more. On tapping the converter and casting an ingot, Bessemer identified the metal as wholly decarburized malleable iron -- the product he desired. And except for melting the crude iron in the first place, no fuel was used.

17 INSERT Figure I.2 Bessemer's Optical Glass Furnace (c. 1850) In the following weeks Bessemer sought to tame the violent blow. To deflect the flame he placed a cast iron grate above the opening, but the white-hot blast melted it. He then tried lessening the blast by decreasing the number of tuyères, their diameter, or the pressure of the air. These changes indeed reduced the heat, in one case leaving an entire converter full of solid iron. Resigning himself to a violent blow, Bessemer sought to contain it in a converter featuring a cone-shaped upper chamber (which strikingly resembles an earlier furnace he devised to melt optical glass; see Figure I.2). This familiar arrangement harmlessly vented the hot gases. With this vertical, fixed, two-chamber converter, Bessemer achieved the successful conversion of crude iron to steel. 18 INSERT Figure I.3 Publicity for Bessemer's First Converter (1856) Bessemer quickly swung his publicity machine into action.

He showed his converter to George Rennie, president of the mechanical sciences section of the British Association for the Advancement of Science (BAAS), where a decade earlier James Neilson had showcased his hot blast furnace, the invention that gave iron smelting its characteristic form and name. Rennie was duly impressed and invited Bessemer to give a talk at the upcoming BAAS meeting in Cheltenham. There, on 13 August 1856, Bessemer presented "The Manufacture of Malleable Iron and Steel without Fuel." If this seemingly absurd concept produced snickers before the talk, few remained afterward. It was "a true British nugget," stated the engineer James Nasmyth. The next day's report in The Times reproducing Bessemer's 2,000 word essay attracted the attention of Edward Riley, chemist of the Dowlais Iron Company, the leading Wales firm. Two weeks after the BAAS talk Dowlais purchased the first license for £10,000, just as the Illustrated London News featured Bessemer's converter in action (see Figure I.3).

Early in September Bessemer staged an exhibition at Baxter House for "some seventy or eighty of the most eminent persons connected with the manufacture of iron." 19 Trial converters were erected in the following months by Dowlais Iron (Wales), Messrs. Galloway. (Manchester), Govan Ironworks (Glasgow), and Butterley Iron (Derbyshire), but their trials were disastrous. Many found the new metal was too brittle to roll or forge into useful shapes; at the rolling mill at Dowlais Iron, for instance, "the ingots ... were crushed into rough gravel like powder, showing a total want of malleability." 20 To diagnose the problem, Bessemer consulted with the prominent metallurgists T. H. Henry.H.; and John Percy, while the Dowlais chemist continued his investigations. Bessemer had by happenstance used a grey Blaenavon pig iron that was exceedingly low in phosphorus content. Nearly all other pig irons available in Britain contained significant amounts of this element, and they yielded an obviously inferior product. Bessemer first tried to improve common grades of British pig iron by using different fluxes and by passing various gases through the liquid metal.

When this line of experiments failed Bessemer decided to switch to Swedish pig iron, a premium grade often used in making Sheffield's fiendishly expensive crucible steel. Finding and matching suitable pig irons was a hit or miss proposition for several years, until the key role of phosphorus -- and especially its relation to brittleness in steel -- was recognized in the early 1860s. It was from bitter experience that Bessemer later remarked, "An invention must be nursed as a mother nurses her baby, or it inevitably perishes." 21 INSERT Figure I.4 Plan of Bessemer Plant at Sheffield (1858) Another problem was that Bessemer had announced his process as if it were trouble-free when it manifestly was not. Backers of the several commercial ventures were especially annoyed that their substantial license payments had not brought them a workable process. Their persistent difficulties eventually forced Bessemer to refund some £32,500 in licensing fees. A complete commercial failure was at hand. What saved Bessemer was his prior experience in developing and commercializing the manufacturing ventures in embossed velvet and bronze powder, and the money he had realized from them.

Bessemer had furthermore retained full rights to his patent. These resources together gave Bessemer the insight and means to build a steel works of his own in Sheffield (see Figure I.4). In 1858 Bessemer formed a partnership with his brothers-in-law Robert Longsdon and William Allen, as well as with his machinery suppliers William and John Galloway of Manchester. For its first year the steel works produced an odd product. A stream of the molten steel was run into a vat of water and solidified as pellets; then a mixture of these pellets from several batches was remelted in one of Sheffield's famous clay crucibles. Only after a visit in 1859 from the Swede Göran Göransson, the first licensee to make commercial quantities of the new steel, did Bessemer begin producing steel directly from the converter without the crucible remelting. While the details of his contribution remain unclear to this date, Göransson may have turned the corner. The Sheffield works lost £1,800 in its first two years of operation (1858-59) then made increasingly handsome profits thereafter.

22 INSERT Figure I.5 Bessemer's Tilting Converters (1858) Yet there is no gainsaying Bessemer's own substantial efforts. He helped commercialize in Cumberland and Lancashire newly discovered beds of non-phosphorus hematite iron ore, which could easily and economically be smelted and converted into a malleable steel that was easily rolled or forged. He also worked to devise a fire brick lining to contain the white-hot metal in the converting vessel. For the Sheffield works in 1858 Bessemer adopted a tiltable converter, a major innovation again prefigured in the optical glass furnace. The physical arrangement of the stationary vertical converter had required that the air blast begin before the crude iron entered the converting vessel and last until the converted steel left; otherwise the metal would simply run out the bottom. The problem was that any delay in casting the converted steel into ingots could result in the air blast cooling the metal, and there was always the spectre of the cold converter filled with solid metal. The solution Bessemer devised was to tilt the converter so that the air blast was needed only for the duration of the converting blow (see Figure I.5).

With this arrangement, minor delays no longer could ruin the batch of steel. With new sources of low-phosphorus pig iron, a more durable vessel lining, and the tilting converter, Bessemer had achieved technical if not yet commercial success. 23 Bessemer's commercial success was a product of his ability to arrange financing, retain patent control, and fend off rivals. Again the publicity machine was fired up. Bessemer's exhibit at the London International Exhibition in 1862 attracted the attention of John Platt -- an engineer and industrialist -- and M.P. from Oldham. Impressed by the process (and by the profits finally coming to the Sheffield works) Platt quickly assembled an investment syndicate that offered to purchase a one-fourth share of the patent. Wary of losing control, Bessemer pressed for a more advantageous deal. The two parties soon came to agreement that the syndicate would make an investment equivalent to a one-fourth share for £50,000 but that Bessemer and Longsdon would retain complete control of the patents, thus retaining the right to grant licenses and to raise or lower royalties.

Three weeks after the Exhibition's opening, the deal was concluded after dinner at the Queen's Hotel in Manchester, when each of the ten investors personally handed £5,000 to Bessemer and Longsdon. This timely infusion of capital added momentum to commercializing the new process. Bessemer's original five partners in the Sheffield works racked up profits over 14 years totalling 8,100 percent, the members of the Platt syndicate, a still-handsome 520 percent. 24 While Bessemer was of course not the only person to experiment with blowing air or steam through molten metal, his ability to coopt potential rivals was unmatched. Following the BAAS paper Bessemer had declined a buy-out offer from the Ebbw Vale Ironworks, another prominent Wales concern. Instead, Ebbw Vale purchased a vaguely similar and therefore rival patent of Joseph G. Martien, and subsequently the firm's own furnace master gained several patents for blowing air into and over various mixtures of scrap iron. Around 1864 Ebbw Vale decided to exploit these patents by forming a new joint stock company with a very large capitalization.

When Bessemer heard of these plans he threatened not only filing a lawsuit but also setting his publicity machine to work covering London's financial district with posters, placards, and handbills to prevent the stock subscription from going forth. In the event a compromise was arranged between Bessemer and the principals of Ebbw Vale, Abraham Darby and Joseph Robinson. It turned out that Ebbw Vale did not actually own the furnace master's patents, which Bessemer purchased for £5,000; the new firm took out a regular license and paid standard royalties, except that Bessemer deducted £25,000 from their first royalties in exchange for the Martien patents. Bessemer now possessed his principal rival's patents, he had another licensee, and, despite the stiff price, he netted some £50,000 or £60,000 from the deal. Thus, as Bessemer put it, "happily was removed the last barrier to the quiet commercial progress of my invention throughout Europe and America." 25 10 . Henry Bessemer, An Autobiography (London: Offices of Engineering, 1905), 121.

11 . See "'Bessemerizing' and the Nitrate Steel Process," Engineer 25 (7 Feb. 1868): 100. 12 . Dictionary of National Biography, s.v., "Sir Henry Bessemer," XXII: 186; Geoffrey Tweedale, s.v. "Sir Henry Bessemer," Dictionary of Business Biography (London: Butterworths, 1984), I: 309-12. 13 . In the near absence of reliable documents, apart from the Dowlais Iron papers, historians must interpret Bessemer's always-boastful and sometimes-unreliable Autobiography. Bessemer's personal papers were apparently destroyed; see Alan Birch, The Economic History of the British Iron and Steel Industry, 1784-1879 (New York: Kelley, 1968), 320 n 19; Jeanne McHugh, Alexander Holley and the Makers of Steel (Baltimore: Johns Hopkins University Press, 1980), 76 n 1.

Notable for comparing Bessemer's account with primary documents is Alan Birch, "Henry Bessemer and the Steel Revolution," Nachrichten aus der Eisen-Bibliothek (Schaffhausen) 28 (1963): 129-36; 30 (1964): 153-59; and Edgar Jones, "The Transition from Wrought Iron to Steel Technology at the Dowlais Iron Company, 1850-1890," in Jonathan Liebenau, ed., The Challenge of New Technology: Innovation in British Business Since 1850 (Gower: Aldershot, 1988), 43-57. On Bessemer as a mechanical inventor see Bessemer, Autobiography, 4-137, 329-32; Ernst F. Lange, "Bessemer, Göransson and Mushet: A Contribution to Technical History," Memoirs Manchester Lit & Phil Society 57 no. 17 (1913): 2-5, 33-8. Bessemer gained a total of 117 patents. 14 .

Bessemer, Autobiography, 134-42, quotes 130, 136-37; Lange, "Bessemer," 4-5. 15 . Blister steel resulted from baking bars of iron that contained essentially no carbon in furnaces filled with charcoal; the process, known as cementation, required as long as a week before the desired amount of carbon in the charcoal diffused into the iron bars, producing blisters on their surface; blister steel melted in clay crucibles became the "crucible steel" that made Sheffield famous. See Geoffrey Tweedale, Sheffield Steel and America: A Century of Commercial and Technological Interdependence, 1830-1930 (Cambridge: Cambridge University Press, 1987), chap. 2. 16 . Bessemer, Autobiography, 142; and Tweedale, "Bessemer," 310. 17 . Bessemer, Autobiography, 142-4, quote 144; Bessemer, "The Origin of the Bessemer Process," Iron Age 58 (3 Dec.

1896): 1065-71; Lange, "Bessemer," 4-5. In modern terms, the oxygen in the air and the silicon and carbon in the metal combined in a violent combustion; such a chemical understanding was yet to emerge. 18 . Bessemer, Autobiography, 144-54; and Henry Bessemer, "On the Manufacture of Cast Steel, Its Progress, and Employment as a Substitute for Wrought Iron," Engineer (London) 20 (15 Sept. 1865): 173-4. 19 . W. T. Jeans, The Creators of the Age of Steel (New York: C. Scribner's Sons; London: Chapman & Hall, 1884), quote 44; Bessemer, Autobiography, 154-68, Nasmyth letter reproduced in figure 93. For the first licenses, see H. Bessemer and R. Longsdon agreement with Dowlais Iron Co. 27 Aug. 1856; Bessemer and Longsdon to G.T. Clark 28 Aug.

1856, 5 Dec. 1856; Bessemer and Longsdon to Dowlais Iron Co. 3 Sept. 1856, D/DG Section C Box 2, DI; Madeleine Elsas, ed., Iron in the Making: Dowlais Iron Company Letters, 1782-1860 (Cardiff: Glamorgan County Council and Guest Keen Iron and Steel, 1960), 193-4, 205-6; Edgar Jones, "Wrought Iron to Steel at Dowlais Iron," 51, gives the Dowlais license at £20,000. 20 . Lowthian Bell, "Invention of the Bessemer Process" MS. 26 Aug. 1903; and Bell to H. M. Howe, 23 Mar. 1899, 3: Patent Applications of Robert Hadfield for the Manufacture of Manganese Steels 1896, HMH. 21 .

Bessemer, Autobiography, quote 121, 170-4, 182-4; Lange, "Bessemer," 7-12. The precise role of Henry and Percy remains unclear. Lowthian Bell doubted that even Blaenavon pig iron could be made into Bessemer steel; Bell "Invention." 22 . W. M. Lord, "The Development of the Bessemer Process in Lancashire, 1856-1900," Newcomen Society Trans. 25 (1945-47): 165-7; W. H. Chaloner, "John Galloway (1804-1894), Engineer of Manchester, and his 'Reminiscences'," in D. A. Farnie and W. O.

Henderson, eds., Industry and Innovation (London: Cass, 1990), 99-121, on 116-17; Bessemer, Autobiography, 171-77, 213-15, 334; Lange, "Bessemer," 13-7; Bessemer, "On the Manufacture of Cast Steel," 173. Total capital for the Sheffield works was £12,000: Bessemer and Longsdon subscribed about £6,000; W. & J. Galloway, £5,000; William D. Allen, £500; Tweedale, "Bessemer," 310-11.

Profit or (loss) for the Sheffield works Bessemer, Autobiography, 334 1858 (£729) 1863 £10,968 1859 (£1093) 1864 £11,827 1860 £923 1865 £3,949 1861 £1,475 1866 £18,076 1862 £3,685 1867 £28,622 23 . Lord, "Development," 169-74; Bessemer, Autobiography, 148-51, 178-81, 256-90; Lange, "Bessemer," 18-20. 24 . According to the Queen's Hotel anecdote, Bessemer's share of the partnership was 80 percent, Longsdon's, 20 percent.

Bessemer, Autobiography, 177, 234-37, 334; Lange, "Bessemer," 28-30. Ironically, Bessemer tried without success to interest the War Department and the Admiralty in his process; Bessemer, Autobiography, 184-255. 25 . For others' experiments treating molten iron with blasts of air or steam similar to Bessemer's see Theodore A. Wertime, The Coming of the Age of Steel (Leiden: E. J. Brill, 1961), 284-87; J. A. Cantrell, James Nasmyth and the Bridgewater Foundry: A Study of Entrepreneurship in the Early Engineering Industry (Manchester: Manchester University Press, 1984), 123-26. Bessemer, Autobiography, 168-70, 291-303, quote 303; Lange, "Bessemer," 21-4. The views and opinions expressed in this page are strictly those of the page author.

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Question: What is produced in a Bessemer Converter?
Answer: STEEL